淹没堆积体附近水流特性研究

Study on Flow Characteristics Near Submerged Congery

堆积体的存在对其附近水流结构产生明显影响,在通过水槽试验数据验证数值模拟结果良好的基础上,开展淹没堆积体附近流场数值模拟研究。结果表明:堆积体在处于淹没状态时,对堆积体顶部以下的水流仍然起到有效调节作用。在近床面流层,高紊动区是主流扩散所导致的,随着流层上升,高紊动区的分布范围和强度主要受到回流区的控制。涡量较大的区域产生于堆积体表面流场、回流区与主流区的交界范围内,由于这两个区域的涡量较大,因此可能更有利于堆积体颗粒的起动及泥沙输移。

The existence of congeries have an obvious influence on the flow structure near it. Based on the good agreement with the numerical simulation results verified by flume test data, the numerical simulation of flow field near submerged congery was carried out. The results show that when the congery is submerged, it still has an effective regulating effect on the water flow below the top of the it. In the surface flow layer near the bed, the high turbulence zone is caused by the mainstream diffusion, with the flow layer rising, the distribution range and intensity of the strong turbulence zone are mainly controlled by the reflux region. The region with high vorticity value is generated at the boundary between the flow field on the surface of the congery and the reflux region and the main flow region. Because the vorticity in these two regions is large, it may be more conducive to the initiation of sediment particles and sediment transport, and have a certain influence to the evolution of the downstream riverbed and the operation of the hydropower station.